System and method for attaching soft tissue to bone

ABSTRACT

A system and method for attaching soft tissue to bone.

FIELD OF THE INVENTION

[0001] This invention relates generally to medical devices andprocedures. More particularly, this invention relates to systems andmethods for attaching soft tissue to bone.

BACKGROUND OF THE INVENTION

[0002] The complete or partial detachment of ligaments, tendons and/orother soft tissues from their associated bones within the body arerelatively commonplace injuries, particularly among athletes. Suchinjuries are generally the result of excessive stresses being placed onthese tissues. By way of example, tissue detachment may occur as theresult of an accident such as a fall, over-exertion during awork-related activity, during the course of an athletic event, or in anyone of many other situations and/or activities.

[0003] In the case of a partial detachment, the injury will frequentlyheal itself, if given sufficient time and if care is taken not to exposethe injury to further undue stress.

[0004] In the case of complete detachment, however, surgery may beneeded to re-attach the soft tissue to its associated bone or bones.

[0005] Numerous devices are currently available to re-attach soft tissueto bone. Examples of such currently-available devices include screws,staples, suture anchors and tacks.

[0006] In soft tissue re-attachment procedures utilizing screws, thedetached soft tissue is typically moved back into its original positionover the bone. Then the screw is screwed through the soft tissue andinto the bone, with the shank and head of the screw holding the softtissue to the bone.

[0007] Similarly, in soft tissue re-attachment procedures utilizingstaples, the detached soft tissue is typically moved back into itsoriginal position over the bone. Then the staple is driven through thesoft tissue and into the bone, with the legs and bridge of the stapleholding the soft tissue to the bone.

[0008] In soft tissue re-attachment procedures utilizing suture anchors,an anchor-receiving hole is generally first drilled in the bone at thedesired point of tissue re-attachment. Then a suture anchor is deployedin the hole using an appropriate installation tool. This effectivelylocks the suture to the bone, with the free end(s) of the sutureextending out of the bone. Next, the soft tissue is moved into positionover the hole containing the deployed suture anchor. As this is done,the free end(s) of the suture is (are) passed through or around the softtissue, so that the free end(s) of the suture reside(s) on the far(i.e., non-bone) side of the soft tissue. Finally, the suture is used totie the soft tissue securely to the bone.

[0009] Alternatively, in some soft tissue re-attachment proceduresutilizing suture anchors of the type described above, the soft tissuemay first be moved into position over the bone. Then, while the softtissue lies in position against the bone, a single hole may be drilledthrough the soft tissue and into the bone. Next, a suture anchor ispassed through the soft tissue and deployed in the bone using anappropriate installation tool. This results in the suture anchor beinglocked to the bone, with the free end(s) of the suture extending out ofthe bone and through the soft tissue. Finally, the suture is used to tiethe soft tissue securely to the bone.

[0010] In some cases, the suture anchor may include drill means at itsdistal end, whereby the suture anchor can be drilled into the bone, ordrilled through the soft tissue and into the bone, whereby theaforementioned drilling and anchor-deployment steps are effectivelycombined.

[0011] Similarly, in soft tissue re-attachment procedures utilizingtacks, the detached soft tissue is typically moved back into itsoriginal position over the bone, and then a tack-receiving hole isgenerally drilled through the soft tissue and into the bone. Then thetack is driven through the soft tissue and into the bone, so that theshaft and head of the tack will hold the soft tissue to the bone.

[0012] While systems and method based on the aforementioned screws,staples, suture anchors and tacks are generally effective, they also allsuffer from one or more disadvantages.

OBJECTS OF THE INVENTION

[0013] Accordingly, one object of the present invention is to provide anovel system and method for re-attaching soft tissue to bone whichimproves upon the prior art devices and techniques discussed above.

[0014] Another object of the present invention is to provide a novelsystem and method for re-attaching soft tissue to bone which is easy touse and simple to perform.

[0015] And another object of the present invention is to provide a novelsystem and method for re-attaching soft tissue to bone which expeditesand facilitates the re-attachment procedure.

[0016] Still another object of the present invention is to provide anovel system and method for re-attaching soft tissue to bone whichminimizes trauma to the patient during the re-attachment procedure.

[0017] Yet another object of the present invention is to provide a novelsystem and method for re-attaching soft tissue to bone which can be usedin both open surgical procedures and in closed surgical procedures(e.g., arthroscopic or endoscopic surgical procedures) where access tothe surgical site is provided by one or more cannulas.

[0018] And another object of the present invention is to provide a novelsystem and method for re-attaching soft tissue to bone which is alsousable in the attachment of prosthetic devices, and/or grafts of naturaland/or synthetic material, to bone or bone-like structures.

SUMMARY OF THE INVENTION

[0019] These and other objects of the present invention are achieved bythe provision and use of a novel system and method for attaching softtissue and the like to bone.

[0020] In one preferred embodiment, the novel system comprises anexpandable body configured to expand into bone, the expandable bodydefining a bore; and an expander pin comprising a shaft sized to bereceived in the bore of the expandable body and expand the expandablebody laterally when the expander pin is driven into the expandable body,and tissue attachment apparatus associated with the shaft, the expanderpin defining a bore; whereby when the expander pin is driven into theexpandable body, the expandable body will be attached to bone and thetissue attachment apparatus will secure tissue to the apparatus.

[0021] In one preferred embodiment, the novel method comprises drivingan expandable fastener into a bone, the expandable fastener defining abore and comprising tissue attachment apparatus; and fixing theexpandable fastener in, and thereby securing the tissue relative to, thebone.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] These and other objects and features of the present inventionwill be more fully disclosed or rendered obvious by the followingdetailed description of the preferred embodiments of the invention,which is to be considered together with the accompanying drawingswherein like numbers refer to like parts, and further wherein:

[0023]FIG. 1 is a side view of a novel fastening system formed inaccordance with the present invention;

[0024] FIGS. 2-4 are perspective views of the distal end of thefastening system shown in FIG. 1;

[0025]FIG. 5 is a side view, partially in section, of the distal end ofthe fastening system shown in FIG. 1;

[0026]FIG. 6 is an exploded view showing the fastener, and a portion ofthe installation tool, of the fastening system shown in FIG. 1;

[0027]FIGS. 7 and 8 are perspective, exploded views of the elementsshown in FIG. 5;

[0028] FIGS. 9-11 show details of the distal tip member of the fastenershown in FIG. 5;

[0029]FIGS. 12 and 13 show details of the proximal main member of thefastener shown in FIG. 5;

[0030] FIGS. 14-16 show details of the expander pin of the fastenershown in FIG. 5;

[0031] FIGS. 17-19 show details of the pusher member of the installationtool shown in FIG. 5;

[0032]FIG. 20 is an exploded side view of the handle assembly of theinstallation tool shown in FIG. 1;

[0033] FIGS. 21-25 show the novel fastening system of the presentinvention being used to attach soft tissue (or the like) to bone;

[0034] FIGS. 26-28 illustrate one preferred form of the novel fasteningsystem of the present invention being used to attach soft tissue (or thelike) to bone;

[0035]FIGS. 29 and 30 illustrate another preferred form of the novelfastening system of the present invention being used to attach softtissue (or the like) to bone;

[0036]FIG. 31 is a side view showing an alternative form of proximalmain member for a fastener formed in accordance with the presentinvention;

[0037]FIG. 32 is a side view showing an alternative form of distal tipmember for a fastener formed in accordance with the present invention;

[0038] FIGS. 33-35 show details of an alternative form of the fastener'sexpander pin;

[0039] FIGS. 36-38 show details of another alternative form of thefastener's expander pin;

[0040] FIGS. 39-42 show details of the construction of an alternativeform of fastener also formed in accordance with the present invention;

[0041]FIGS. 43 and 44 show the fastener of FIGS. 39-42 being used toattach soft tissue (or the like) to bone;

[0042]FIG. 45 shows details of an alternative form of expander pin forthe fastener shown in FIGS. 39-44;

[0043] FIGS. 46-49 show details of the construction of anotheralternative form of fastener also formed in accordance with the presentinvention;

[0044] FIGS. 50-53 show the fastener of FIGS. 46-49 being used to attachsoft tissue (or the like) to bone;

[0045]FIG. 54 shows details of an alternative form of expander pin forthe fastener shown in FIGS. 46-53; and

[0046]FIGS. 55 and 56 show details of a removal tool for removing afastener formed and deployed in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0047] Looking first at FIG. 1, there is shown a fastening system 5 forattaching soft tissue (or the like) to bone. Fastening system 5generally comprises a fastener 10 and an installation tool 15.

[0048] Looking next at FIGS. 1-8, fastener 10 generally comprises anexpandable body 100 (FIG. 2) and an expander pin 200.

[0049] Expandable body 100 comprises a generally frusto-conical distalend 105 (FIG. 5) characterized by a frusto-conical outer surface 110terminating in a distal end surface (or rim) 115, and a generallycylindrical proximal end 120 terminating in a proximal end surface 125.A central passageway 130 extends through expandable body 100, fromdistal end surface 115 to proximal end surface 125.

[0050] In a preferred form of the invention, central passageway 130comprises a bore 135 opening on distal end surface 115, a threadedsection 140, and a bore 145 opening on proximal end surface 125.

[0051] Expandable body 100 preferably also comprises bone securementapparatus 150 formed on proximal end 120 for facilitating securement offastener s to bone, as will hereinafter be discussed in further detail.In one preferred form of the invention, bone securement apparatus 150comprises a plurality of frusto-conical ribs 155. Ribs 155 are tapered,distally-to-proximally, so as to (1) facilitate insertion of expandablebody 100 into bone in a distal direction, and (2) resist withdrawal ofexpandable body 100 from bone in a proximal direction.

[0052] If desired, expandable body 100 can be formed out of a singlepiece of material. Preferably, however, and looking now at FIGS. 1-13,expandable body 100 comprises a distal tip member 160 (FIG. 9) and aproximal main member 165 (FIG. 12).

[0053] Distal tip member 160 (FIGS. 9-11) preferably comprises theaforementioned frusto-conical outer surface 110, distal end surface (orrim) 115, internal bore 135, and threaded section 140. Distal tip member160 also preferably comprises a proximally-extending, threadedprojection 170. Proximally-extending threaded projection 170 serves tosecure distal tip member 160 to proximal main member 165, as willhereinafter be discussed in further detail.

[0054] Proximal main member 165 (FIGS. 12 and 13) preferably comprisesthe aforementioned proximal end surface 125, bore 145 and bonesecurement apparatus 150 (preferably in the form of frusto-conical ribs155). Proximal main member 165 also comprises a threaded counterbore 175at its distal end. Threaded counterbore 175 is sized and shaped so as tomatingly receive proximally-extending threaded projection 170 of distaltip member 160, whereby the two elements may be secured to one anotherso as to form the complete expandable body 100.

[0055] A primary advantage of forming expandable body 100 out of twoseparate components (i.e., distal tip member 160 and proximal mainmember 165) is that each component can be optimized for its ownfunction. More particularly, inasmuch as distal tip member 160 isintended to help open a passageway in bone to receive the overallfastener 10, distal tip member 160 is preferably formed out of arelatively hard material. At the same time, however, inasmuch asproximal main member 165 is intended to expand radially outwardly duringdeployment of the fastener so as to fix expandable body 100 (and hencethe complete fastener 10) to bone, proximal main member 165 ispreferably formed out a relatively soft and easily expandable material.

[0056] Fastener 10 also comprises the expander pin 200. Looking next atFIGS. 1-8 and 14-16, expander pin 200 generally comprises a shaft 205and tissue attachment apparatus 210 associated with shaft 205. Shaft 205is sized so that it will not normally fit within central passageway 130(FIG. 5) of expandable body 100. However, shaft 205 is also sized sothat when expander pin 200 is driven longitudinally into expandable body100, the expander pin will force the side walls of expandable body 100to expand radially outwardly against adjacent bone, whereby theexpandable body (and hence the entire fastener) will be secured to ahost bone, as will hereinafter be discussed in further detail.

[0057] Preferably, shaft 205 includes fastener stabilization apparatus215 for stabilizing the longitudinal position of expander pin 200relative to expandable body 100, as will hereinafter be discussed infurther detail. More particularly, fastener stabilization apparatus 215is adapted to resist withdrawal of expander pin 200 from expandable body100 once expander pin 200 has been driven into expandable body 100, aswill hereinafter be discussed in further detail. In one preferred formof the invention, fastener stabilization apparatus 215 comprises a screwthread 220 formed on the outer surface of shaft 205.

[0058] Still looking now at FIGS. 1-8 and 14-16, in one preferred formof the invention, tissue attachment apparatus 210 comprises one or morelateral projections 225 adjacent to the proximal end of the shaft. Theone or more lateral projections 225 collectively form a fastener headfor holding tissue to bone, as will hereinafter be discussed in furtherdetail.

[0059] Expander pin 200 includes a longitudinal passageway 230 extendingthe length of the expander pin.

[0060] Fastener 10 is intended to be used in conjunction withinstallation tool 15. Looking next at FIGS. 1-8, installation tool 15comprises a shaft 300 (FIG. 6) terminating in a tapered distal point310. Tapered distal point 310 is preferably formed so as to berelatively hard; whereby it can open a passageway in bone to receive theoverall fastener 10, as will hereinafter be discussed in further detail.Threads 315 are formed on shaft 300 proximal to tapered distal point310. Shaft 300 is sized so that it may be received in the centralpassageway 130 (FIG. 5) of expandable body 100, and in longitudinalpassageway 230 (FIG. 16) of expander pin 200. Threads 315 of shaft 300are sized and positioned so that when fastener 10 (i.e., expandable body100 and expander pin 200) is mounted on shaft 300, shaft threads 315 canmate with the expandable body's threads 140, whereby expandable body 100can be secured to the distal end of shaft 300. In one preferred form ofthe invention, the shaft's tapered distal point 310 and the expandablebody's frusto-conical outer surface 110 (FIG. 9) are coordinated withone another so that when expandable body 100 is screwed onto shaft 300,the expandable body's frusto-conical outer surface 110 will form, in arough sense, a continuation, or extension, of the taper of the shaft'stapered distal point 310 (FIG. 5).

[0061] Preferably, the installation tool's shaft 300 comprises a thinnerdistal section 320 (FIG. 5) proximal to the shaft's tapered distal point310 and distal to the shaft's threads 315, and a trailing section 325proximal to shaft threads 315, and a thicker proximal section 330proximal to trailing section 325. Trailing section 325 and thickerproximal section 330 together define an annular shoulder 335 at theirintersection. A rib 340 is preferably formed on trailing section 325,distal to annular shoulder 335.

[0062] A pusher 400 (FIGS. 5 and 17) is preferably mounted on shaft 300.Pusher 400 is used to help deploy fastener 10 in bone, by transferring aforce applied to the proximal end of pusher 400 onto a fastener 10located at the distal end of pusher 400. In the process, pusher 400 actsas a sort of safeguard to prevent the proximal end of fastener 10 (i.e.,the proximal end of expander pin 200) from being damaged during theapplication of such force. Pusher 400 preferably comprises a tapereddistal portion 405 characterized by a tapered outer surface 410terminating in a distal end surface 415, and a cylindrical proximalportion 420 characterized by a cylindrical outer surface 425 terminatingin a proximal end surface 427. Pusher 400 has a central bore 430extending therethrough. Bore 430 is sized so that it will form a closesliding fit with rib 340 (FIG. 6) of shaft 300. A lip 435 (FIG. 17)protrudes into central bore 430 adjacent to the pusher's proximal endsurface 427. Lip 435 is sized so that it may not pass by rib 340 ofshaft 300.

[0063] In one preferred form of the invention, shaft 300 includes aplurality of ribs 345 (FIG. 6) on the shaft's thicker proximal section330, and installation tool 15 includes a handle assembly 500 (FIG. 20).Each rib 345 includes an inclined surface 345A disposed on the proximalside of the rib (FIG. 6). The distal side of each rib 345 extendssubstantially perpendicular to the longitudinal axis of shaft 300.

[0064] Handle assembly 500 comprises a body 501 having a handle grip502. A trigger 505, having a plurality of fingers 507, is pivotallyconnected to body 501. Body 501 also comprises a bore 508 opening on thebody's distal end, and a counterbore 509 opening on the body's proximalend. A shoulder 509A is formed at the intersection of bore 508 andcounterbore 509.

[0065] Handle assembly 500 also comprises a hollow ram 515. Ram 515 issized so that it can slidably accommodate shaft 300, as will hereinafterbe discussed in further detail. Ram 515 comprises a narrower distalportion 520 terminating in a distal tip 510, and a wider proximalportion 525 including a plurality of teeth 530. A shoulder 535 is formedat the intersection of narrower distal portion 520 and wider proximalportion 525. A slot 540 extends through the side wall of narrower distalportion 520.

[0066] Ram 515 is mounted in body 510 in the manner shown in FIGS. 1 and20, i.e., so that (1) the ram's narrower distal portion 520 extendsthrough, and protrudes from, the body's bore 508, (2) the ram's widerproximal portion 525 is disposed in the body's counterbore 509, and (3)the trigger's fingers 507 engage the ram's teeth 530. As a result ofthis construction, moving trigger 505 will cause ram 515 to moverelative to body 501. A spring 545 is positioned in body 501, betweenbody shoulder 509A and ram shoulder 535, so as to bias ram 515 in aproximal direction. A stop pin 550 extends into counterbore 509 so as tolimit proximal movement of ram 515.

[0067] Handle assembly 500 also comprises a gate 555 which includes anopening 560 therein. Opening 560 defines a bottom wall 565 thereof. Gate555 is disposed in an opening 570 formed in body 501. A spring 575biases gate 555 against a locking pin 580, which extends through anoversized hole 585 formed in gate 555. Gate 555 is disposed in body 501so that the gate's bottom wall 565 normally protrudes, via ram slot 540,into the interior of ram 515; however, pressing gate 555 downwardagainst the power of spring 575 will permit the gate's bottom wall 565to be removed from the interior of ram 515.

[0068] In use, and as will hereinafter be discussed in further detail,handle assembly 500 is loaded over the proximal end of shaft 300, andmoved proximally down the shaft until the gate's bottom wall 565 startsto engage the ribs 345 of shaft 300. As this occurs, the inclinedproximal surfaces 345A of ribs 345 will allow the handle assembly 500 tobe moved distally along shaft 300 to the extent desired. However, sinceinclined surfaces 345A are provided on only the proximal sides of ribs345, the geometry of the ribs will prevent handle assembly 500 frommoving back proximally along the shaft, unless gate 555 is presseddownward against the power of spring 575 so as to move the gate's bottomwall 565 out of engagement with the shaft's ribs. Handle assembly 500 ismoved down shaft 300 until the ram's distal end surface 510 engages, orsubstantially engages, the proximal end 427 of pusher 400. Thereafter,pulling of the handle assembly's trigger 505 will cause ram 515 to movedistally along shaft 300, whereby pusher 400 can drive expander pin 200into expandable body 100 so as to set the expandable body in bone, aswill hereinafter be discussed in further detail.

[0069] The use of handle assembly 500 in conjunction with shaft 300 isoften preferred, since it permits shaft 300 to be held in-place whileram 515 is advanced down shaft 300. More particularly, inasmuch ashandle assembly 500 is releasably secured to shaft 300 via theengagement of handle gate 555 with shaft ribs 345, handle assembly 500can stabilize shaft 300 even as the handle's ram 515 is advancing downshaft 300. This has been found to be advantageous in many circumstances.However, it should also be appreciated that fastener 10 can be setwithout using handle assembly 500, as will hereinafter also be discussedin further detail.

[0070] Looking next at FIGS. 21-25, there is shown a general method forattaching soft tissue (or the like) to bone using the fastener of thepresent invention. In particular, the invention will be discussed in thecontext of (1) a fastener 10 comprising an expandable body 100 and anexpander pin 200; (2) an installation tool 15 comprising a shaft 300;and (3) a pusher 400 mounted on shaft 300.

[0071] The foregoing fastening system is prepared for use by firstpassing pusher 400 proximally over the distal end of shaft 300 until thepusher's proximal end surface 427 (FIG. 17) engages, or approximatelyengages, the shaft's annular shoulder 335 (FIG. 6). Then the fastener'sexpander pin 200 is passed proximally over the distal end of shaft 300until the proximal end of expander pin 200 engages, or approximatelyengages, the pusher's distal end surface 415 (FIG. 17). Next, thefastener's expandable body 100 is passed proximally over the distal endof shaft 300 until the proximal end of the expandable body's threadedsection 140 (FIG. 5) engages the distal end of the shaft's threads 315(FIG. 6). Then the fastener's expandable body 100 is screwed onto shaft300. At this point, the proximal end surface 125 (FIG. 12) of expandablebody 100 will engage, or approximately engage, the distal end surface ofexpander pin 200. It will be appreciated that at this point, theexpandable body 100, expander pin 200 and pusher 400 will be heldrelatively immobile on shaft 300, by virtue of shaft shoulder 335 (FIG.6) and shaft threads 315 and the sizing of the elements heldtherebetween.

[0072] Next, soft tissue (or the like) 600 is “stabbed” with the sharpdistal point of shaft 300 and dragged to its desired position againstbone 700 (FIG. 21). Alternatively, soft tissue 600 may be gripped byanother instrument (e.g., forceps or the like) and moved into positionagainst bone 700.

[0073] Then, with soft tissue 600 in position against bone 700, shaft300 is forced distally through tissue 600 (FIG. 22) and into bone 700(FIG. 23). It will be appreciated that, as this occurs, expandable body100 will be carried into the bone, due to the screw engagementestablished between expandable body 100 and shaft 300. In fact, thetapered distal ends of shaft 300 and expandable body 100 will cooperatewith one another so as to force an opening in the soft tissue and thebone, without any need for pre-drilling. Shaft 300 is preferably driveninto bone 700 until the proximal end surface 125 of expandable body 100is approximately even with the outer surface of bone 700 (FIG. 23). Ifdesired, markings (not shown) may be placed on the outer surface of thefastener's expander pin 200 so that, once the thickness of soft tissue600 is known, proper depth penetration can be achieved.

[0074] Next, the proximal end of pusher 400 is engaged with anotherelement (not shown in FIGS. 21-25, but shown in subsequent figures) soas to move the pusher distally along shaft 300. Pusher 400 is moveddistally so as to drive expander pin 200 distally, into the centralpassageway 130 (FIG. 5) of expandable body 100, whereby to drive theside walls of expandable body 100 radially outwardly into bone 700 andthereby secure fastener 10 to bone 700 (FIG. 24). At the same time, thefastener's tissue attachment apparatus 210 will secure soft tissue 600to the bone. More particularly, as seen in FIG. 24, the head of expanderpin 200 (made up of one or more lateral projections 225) will beardistally against soft tissue 600, whereby to keep the soft tissue fixedagainst bone 700.

[0075] Finally, shaft 300 is unscrewed from the expandable body'sthreads 140 (FIG. 5) and removed (FIG. 25), leaving fastener 10 securingsoft tissue 600 to bone 700.

[0076] As noted above, in one preferred form of the invention,installation tool 15 is constructed so that shaft 300 includes ribs 345(FIG. 6) adjacent its proximal end, and the installation tool includeshandle assembly 500 (FIG. 20). FIGS. 26-28 illustrate how soft tissue600 may be attached to bone 700 using such an arrangement. Moreparticularly, after pusher 400, expander pin 200 and expandable body 100have been attached to shaft 300 in the manner described above withrespect to FIGS. 21-25, and either before or after shaft 300 is driventhrough soft tissue 600 and into bone 700 to the point shown in FIGS. 23and 26, handle assembly 500 is passed distally over the proximal end ofshaft 300 until the gate 555 engages ribs 345 of shaft 300. Handleassembly 500 is then pushed further down shaft 300 until the distal tip510 of ram 515 engages the proximal end of pusher 400. Then trigger 505is activated so as to move ram 515 distally relative to pusher 400 andfastener 10, whereby the distal tip 510 (FIG. 20) of the handleassembly's ram 515 will drive distally against the proximal end ofpusher 400. This will cause pusher 400 to move expander pin 200distally, whereby to fix fastener 10 in bone 700, with the fastener'shead fixing soft tissue 600 to bone 700 (FIG. 27). Then handle assembly500 is removed proximally off shaft 300, i.e., by first pressing gate555 downward against the power of spring 575 so as to move the gate'sbottom wall 565 out of engagement with ribs 345, and then pulling thehandle assembly 500 proximally off the shaft. Then shaft 300 isunscrewed from the expandable body's threads 140 and removed from thesurgical site (FIG. 28).

[0077] It will be appreciated that, by virtue of the relative sizing ofshaft rib 340 (FIG. 6) and pusher lip 435 (FIG. 17), pusher 400 will beslidably retained on the distal end of shaft 300 even after shaft 300has been unscrewed from fastener 10, since pusher lip 435 will be unableto move past shaft rib 340.

[0078] As noted above, the use of handle assembly 500 in conjunctionwith shaft 300 is frequently preferred, since it permits shaft 300 to beheld in place while ram 515 is advanced down shaft 300. Moreparticularly, inasmuch as handle assembly 500 is releasably secured toshaft 300 via the engagement of handle gate 555 with shaft ribs 345,handle assembly 500 can stabilize shaft 300 even as the handle's ram 515is advancing down shaft 300. In other words, since the fastener'sexpandable body 100 is connected to shaft 300 by the expandable body'sthreaded section 140 and shaft threads 315, and inasmuch as handleassembly 500 is releasably secured to shaft 300 via the engagement ofhandle gate 555 with shaft ribs 345, the handle assembly can advance itsram 515 against the fastener's expander pin 200 even while the handleassembly is holding the shaft 300, and hence the fastener's expandablebody 100, in place. In effect, the use of handle assembly 500 inconjunction with shaft 300 permits a proximally-directed counterforce tobe applied to expandable body 100 even as a distally-directed settingforce is being applied to expander pin 200.

[0079] However, it should also be appreciated that fastener 10 can beset without using handle assembly 500, as will hereinafter be discussedin further detail.

[0080] Thus, in another preferred form of the invention, installationtool 15 may be constructed so that shaft 300 omits ribs 345 on itsproximal end, and so that the installation tool 15 does not includehandle assembly 500. In this case, pusher 400 may be moved proximally onshaft 300 by other means.

[0081] For example, and looking now at FIGS. 29 and 30, a cannulateddriver 800, such as one having a so-called “slap hammer” configuration,can be used to drive pusher 400 distally on shaft 300, whereby tocomplete setting of fastener 10 in bone 700.

[0082] While the “slap hammer” construction shown in FIGS. 29 and 30 issimple and effective, it does suffer from the disadvantage that aproximally-directed counterforce is not being applied to expandable body200 even as the distally-directed setting force is being applied toexpander pin 300, as is the case with the use of handle assembly 500described above.

[0083] It should be appreciated that, if desired, the expandable body'sbone securement apparatus 150 (FIG. 12) may be omitted or,alternatively, replaced by a configuration different than the ribs 155(FIG. 12) previously disclosed. By way of example but not limitation,bone securement apparatus 150 may comprise screw threads 155A shown inFIG. 31.

[0084] It should also be appreciated that, if desired, the expandablebody's distal end 105 (FIG. 5) may have a configuration other than thesmooth, frusto-conical one disclosed above. By way of example but notlimitation, expandable body 100 may have screw threads formed on itstapered distal end. See, for example, FIG. 32, which shows the screwthreads 110A formed on distal tip member 160.

[0085] FIGS. 33-35 show an alternative form of expander pin 200. Moreparticularly, the expander pin 200 shown in FIGS. 33-35 is similar tothe expander pin 200 shown in FIGS. 14-16, except that with the expanderpin of FIGS. 33-35, lateral projections 225A have their outlying edges226 rounded into an arc-like configuration.

[0086] FIGS. 36-38 show yet another alternative form of expander pin200. More particularly, the expander pin 200 shown in FIGS. 36-38 issimilar to the expander pin 200 shown in FIGS. 14-16, except that withthe expander pin of FIGS. 36-38, fastener stabilization apparatus 215comprises a plurality of frusto-conical ribs 220A, rather than the screwthread 220 shown in FIGS. 14-16.

[0087] It is also possible to form the fastener's tissue attachmentapparatus 210 with a different configuration (and with a differentmanner of operation) than the tissue attachment apparatus shown in FIGS.14-16 or 33-36.

[0088] More particularly, with the tissue attachment apparatus 210 shownin FIGS. 14-16 and 33-36, the tissue attachment apparatus essentiallycomprises a head for capturing the soft tissue to bone. However, it isalso contemplated that tissue attachment apparatus 210 may comprise asuture-based mechanism for capturing the soft tissue to bone.

[0089] More particularly, and looking now at FIGS. 39-42, there is showna fastener 10 in which tissue attachment apparatus 210 comprises aplurality of transverse bores 227 formed in expander pin 200 adjacent toits proximal end. Bores 227 accommodate one or more lengths of suture228 (FIG. 39) which may be used to tie a piece of soft tissue (or thelike) to bone. In one preferred form of the invention, expander pin 200includes a cylindrical proximal end portion 229 (FIG. 40) having adiameter larger than the diameter of the central passageway 130 (FIG. 5)of expandable body 100, with transverse bores 227 being formed incylindrical proximal end portion 229.

[0090] In use, the fastener is set through soft tissue 600 and into bone700 in the normal manner (FIGS. 43 and 44); however, since the fastenerlacks the lateral projections 225 (FIG. 14) previously disclosed, theproximal end of expander pin 200 will pass through soft tissue 600without binding it to the bone (FIG. 44). However, sutures 228 willextend out of bone 700 and through soft tissue 600. As a result, thesesutures may then be used to tie the soft tissue down to the bone.

[0091] If desired, the expander pin 200 shown in FIGS. 39-44 can bemodified so as to have its fastener stabilization apparatus 215 in theform of ribs 220A (FIG. 45), rather than the screw thread 220 shown inFIG. 40.

[0092] With respect to the fastener configuration shown in FIGS. 39-45,it should be appreciated that by positioning transverse bores 227 (FIG.40) in the diametrically-enlarged proximal end portion 229, thetransverse bores 227 will remain proximal to expandable body 100 evenafter setting of the fastener (FIG. 44). As a result of thisconstruction, sutures 228 will be able to slip within bores 227 evenafter fastener 10 has been completely deployed in bone 700. As will beapparent to persons skilled in the art, this can be advantageous in somecircumstances during tissue fixation.

[0093] It is also possible to fabricate a fastener 10 with asuture-based mechanism for capturing soft tissue to bone, but where thesutures are prevented from slipping relative to the fastener once thefastener has been fully deployed in the bone.

[0094] More particularly, and looking now at FIGS. 46-49, there is showna fastener 10 which includes an expander pin 200 having a plurality oftransverse bores 227 intermediate its length (FIG. 47). Bores 227accommodate the one or more lengths of suture 228 which may be used totie a piece of soft tissue (or the like) to bone. In one preferred formof the invention, expander pin 200 includes a cylindrical intermediateportion 229A (FIG. 47) having a diameter substantially the same as theremainder of the expander pin, with transverse bores 227 being formed inthe cylindrical intermediate portion 229A.

[0095] Looking next at FIGS. 50-53, in one preferred method of use,shaft 300 and expandable body 100 are driven into bone, and then a pieceof suture 228 is looped around the soft tissue 600 which is to beattached to the bone 700 (FIG. 50). Then the suture 228 is pulled tautso as to bring the soft tissue into close proximity to the fastener(FIG. 51). Then pusher 400 is driven distally (FIG. 52) so as tocompletely set the fastener. At this point, since suture 228 is attachedto expander pin 200 intermediate the length of the expander pin, thesuture will be fixed in place relative to the deployed expander pin and,hence, will secure soft tissue 600 to bone 700. Installation tool 15 isthen removed from the surgical site by unscrewing shaft 300 fromexpandable body 100 (FIG. 53).

[0096] If desired, expander pin 200 can also be formed so that itssuture-receiving bores 227 are located adjacent to the distal end of theexpander pin. For example, in another preferred form of the invention,expander pin 200 includes a cylindrical distal end portion 229B (FIG.54) having a diameter substantially the same as the remainder of theexpander pin, with transverse bores 227 being formed in the cylindricaldistal end portion.

[0097] Looking next at FIGS. 55 and 56, there is shown a removal tool800. Removal tool 800 can be used to remove a previously-deployedfastener 10, if the same should prove necessary or desirable. Removaltool 800 generally comprises a shaft 805 having a reverse thread 810formed on its distal end and a handle 815 formed on its proximal end.The distal end of removal tool 800 is sized so as to be significantlylarger than the longitudinal passageway 230 (FIG. 16) formed in expanderpin 200.

[0098] When a previously-deployed fastener 10 is to be removed, thedistal end of removal tool 800 is screwed into the proximal end ofexpander pin 200 using the removal tool's reverse screw thread 810.Inasmuch as the distal end of the removal tool is significantly largerthan the longitudinal passageway 230 formed in expander pin 200, thisaction will cause the removal tool's distal threads 815 to force theirway into the side wall of expander pin 200 and, depending on the sizingof the removal tool, possibly into the side wall of expandable body 100as well. In any case, as the reverse thread 810 of the removal tool isscrewed into the expander pin, continued reverse screwing willeventually cause the normally-threaded expander pin 200 to unscrewitself from expandable body 100. Removal tool 800 may then be used toremove expander pin 200 from expandable body 100. Expandable body 100may then itself be removed from the surgical site by passing shaft 300back into the interior of expandable body 100, screwing the shaft'sthreads 315 into the expandable body's threaded section 140, and thenremoving the shaft and expandable body from the bone.

What is claimed is:
 1. Apparatus for attaching tissue to bonecomprising: an expandable body configured to expand into bone, saidexpandable body defining a bore; and an expander pin comprising a shaftsized to be received in said bore of said expandable body and expandsaid expandable body laterally when said expander pin is driven intosaid expandable body, and tissue attachment apparatus associated withsaid shaft, said expander pin defining a bore; whereby when saidexpander pin is driven into said expandable body, said expandable bodywill be attached to bone and said tissue attachment apparatus willsecure tissue to said apparatus.
 2. Apparatus according to claim 1wherein said expander pin includes fastener stabilization apparatus forstabilizing said expander pin relative to said expandable body. 3.Apparatus according to claim 2 wherein said fastener stabilizationapparatus comprises threads.
 4. Apparatus according to claim 2 whereinsaid fastener stabilization apparatus comprises ribs.
 5. Apparatusaccording to claim 1 wherein said tissue attachment apparatus comprisesat least one laterally-extending projection for tacking tissue. 6.Apparatus according to claim 5 wherein said at least onelaterally-extending projection has a substantially linear outer edge. 7.Apparatus according to claim 5 wherein said at least onelaterally-extending projection has a substantially arc-like outer edge.8. Apparatus according to claim 1 wherein said tissue attachmentapparatus comprises a bore formed in said expander pin and a sutureextending through said bore.
 9. Apparatus according to claim 8 whereinsaid tissue attachment apparatus is configured so that said suture mayslide relative to said expander pin when said expander pin is receivedin said expandable body.
 10. Apparatus according to claim 8 wherein saidtissue attachment apparatus further comprises a second bore formed insaid expander pin and a second suture extending through said secondbore.
 11. Apparatus according to claim 1 wherein said expander pin hasindicia for indicating depth.
 12. Apparatus according to claim 1 whereinsaid expandable body has a tapered distal end.
 13. Apparatus accordingto claim 1 wherein said expandable body comprises a distal tip memberand a proximal main member, said distal tip member being separable fromsaid proximal main member.
 14. Apparatus according to claim 13 whereinsaid distal tip member and said proximal main member are threadinglyinterengageable with one another.
 15. Apparatus according to claim 13wherein said distal tip member and said proximal main member arefrictionally interengageable with one another.
 16. Apparatus accordingto claim 1 wherein said expandable body comprises a distal tip memberconstructed from a first material and a proximal main member constructedfrom a second material, and wherein said first material is harder thansaid second material.
 17. Apparatus according to claim 1 wherein saidexpandable body includes bone securement apparatus for securing saidexpandable body relative to bone.
 18. Apparatus according to claim 17wherein said bone securement apparatus comprises ribs.
 19. Apparatusaccording to claim 17 wherein said bone securement apparatus comprisesthreads.
 20. Apparatus according to claim 1 wherein said apparatusfurther comprises an installation tool, and wherein said installationtool comprises a shaft sized to be slidingly received in said bore ofsaid expandable body and in said bore of said expander pin. 21.Apparatus according to claim 20 wherein said shaft is releasablyattachable to said expandable body.
 22. Apparatus according to claim 20wherein said shaft and said expandable body are threadinglyinterengageable with one another.
 23. Apparatus according to claim 20wherein said shaft has a tapered distal end.
 24. Apparatus according toclaim 20 wherein said shaft extends distally beyond said expandable bodywhen said shaft is slidingly received in said bore of said expandablebody.
 25. Apparatus according to claim 20 wherein said apparatus furthercomprises a pusher member configured to drive said expander pin intosaid expandable body.
 26. Apparatus according to claim 25 wherein saidpusher member slides along said shaft when driving said expander pininto said expandable body.
 27. Apparatus according to claim 1 whereinsaid apparatus further comprises a cannulated driver assembly adapted todrive said expander pin into said expandable body.
 28. Apparatusaccording to claim 27 wherein said cannulated driver assembly slidesalong a shaft connected to said expandable body.
 29. Apparatus accordingto claim 27 wherein said cannulated driver assembly includes a triggerfor inducing the driving of said expander pin.
 30. Apparatus accordingto claim 27 wherein said cannulated driver assembly comprises a slaphammer.
 31. A method for attaching tissue to bone comprising: driving anexpandable body into a bone, the expandable body defining a bore andcomprising tissue attachment apparatus; and fixing the expandable bodyin, and thereby securing the tissue relative to, the bone.
 32. A methodaccording to claim 31 wherein said fixing includes engaging saidexpandable body with a shaft configured to penetrate the bone.
 33. Amethod according to claim 32, including driving said shaft into thebone.
 34. A method according to claim 31 wherein said fixing comprisesexpanding the expandable body.
 35. A method according to claim 34wherein said expanding includes driving an expander pin into saidexpandable body.
 36. A method according to claim 35 wherein said drivingincludes pushing a pusher member against said expander pin.
 37. A methodaccording to claim 35 wherein said driving includes actuating acannulated driver assembly.
 38. A method according to claim 37 whereinsaid cannulated driver assembly includes a trigger for inducing saiddriving.
 39. A method according to claim 37 wherein said cannulateddriver assembly comprises a slap hammer.
 40. A method according to claim31 wherein said securing includes capturing the tissue against the bone.41. A method according to claim 31 wherein said securing includesrestraining the tissue with suture.
 42. A method according to claim 41wherein said suture slides relative to said expandable body followingsaid fixing.
 43. A method according to claim 41 wherein said securingincludes restraining the tissue with a second suture.
 44. Apparatus forattaching tissue to bone comprising: an installation tool comprising ashaft having a distal end and a proximal end, said distal end of saidshaft terminating in a relatively hard distal point; an expandable bodyconfigured to expand into bone, said expandable body comprising a distalend and a proximal end, an opening extending from said distal end tosaid proximal end, said opening being sized to receive said shaft ofsaid installation tool, and connecting apparatus for connecting saidexpandable body to said shaft of said installation tool when said distalend of said shaft of said installation tool protrudes from said distalend of said expandable body; and an expander pin comprising a shaftsized to be received in said opening in said expandable body and expandsaid expandable body radially when said expander pin is driven distallyinto said expandable body, and tissue attachment apparatus associatedwith said shaft of said expander pin, said expander pin defining a boresized to receive said shaft of said installation tool; whereby when saidexpander pin is driven into said expandable body, said expandable bodywill be attached to bone and said tissue attachment apparatus willsecure tissue to said apparatus.
 45. Apparatus for attaching tissue tobone comprising: a shaft; an expandable body configured to expand intobone, said expandable body defining an opening, and said expandable bodycomprising connection apparatus for connecting said shaft to saidexpandable body; an expander pin comprising a shaft sized to be receivedin said opening in said expandable body and expand said expandable bodyradially when said expander pin is driven into said expandable body; andtissue attachment apparatus associated with at least one of saidexpandable body and said expander pin; whereby when shaft is connectedto said expandable body, and said expander pin is driven into saidexpandable body, said shaft can provide a counterforce to saidexpandable body so as to counteract the driving force applied to saidexpander pin.